Robotic delivery and retrieval of crates to and from non-uniformly sized storage spaces in a versatile shelving array

ABSTRACT

A storage setup and method for robotic delivery and retrieval of crates from shelving blocks are disclosed. At least one shelving block in the setup comprises non-uniformly spaced apart storage surfaces. The storage surfaces are accessible to lift-robots through a network of tracks comprising intersecting vertically and horizontally oriented tracks. A computerized control system is configured to differentiate between storage locations based on which crate sizes from at least two different ranges of crate sizes a storage location can store. The storage may be automatically optimized by routing robots to store crates in storage locations sized in correlation with the size of the crate to be stored.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/461,243 filed Feb. 21, 2017, entitled “LIFT ROBOT CONFIGURATIONS”,which is hereby incorporated by reference in its entirety without givingrise to disavowment.

TECHNICAL FIELD

The present disclosure generally relates to the field of shelvinginfrastructures for fully-automated or semi-automated distribution andretrieval of crates in logistic distribution centers.

BACKGROUND

Modern logistic centers often make use of conveyors and/or robots in thefully-automated or semi-automated processes of distribution of crates totheir designated locations in a shelving array, as well as of returningstored crates upon demand.

Much care is given to the performances of robots, and efforts are madeto improve the efficiency of a logistic centers by improving theperformance of robots based on cutting edge technologies.

It is therefore among the object of the disclosed subject matter tooptimize the performances of logistic centers from the point of view ofthe storage facilities with which the robots interact.

Another object of the disclosed subject matter is to improve theperformances of robots and of robotic interactions, based on theimprovements to the storage facilities.

Other objects of the disclosed subject matter will become more apparentthroughout the specification that follows.

BRIEF SUMMARY

A first broad aspect the presently disclosed subject matter is a storagesetup for logistic centers using lift robots for storing and retrievingcrates.

In one exemplary embodiment of said first broad aspect, the storagesetup comprises: (i) at least one shelving block comprising at least oneshelving unit, wherein each shelving unit having a plurality ofhorizontally oriented vertically spaced apart storage surfacesconfigured to store thereon crates of a size within a predetermineddepth width and height range of sizes; (ii) a network of intersectingtrack arrays deployed next to the block's shelving for allowing roboticdelivery and retrieval of crates to and from storage locations in theshelving block; and (iii) a computerized control system in which storagelocations and track data are registered such that robots can be routedby the computerized control system through the tracks for deliveringcrates to and retrieving crates from the storage locations; wherein atleast two groups of storage locations in at least one shelving blockdiffer in the size of the vertical spacing between horizontally orientedstorage surfaces such that crates of a height shorter than the size ofthe vertical spacing in at least one of the groups but taller than thesize of the vertical spacing in other of the groups can be roboticallystored to and retrieved from a horizontally oriented storage surfaceconstituting a storage location in which the vertical spacing is of asize greater than a height of the crate; wherein the computerizedcontrol system is configured to differentiate between storage locationsbased on which crate sizes from at least two different ranges of cratesizes a storage location is capable of storing.

In various embodiments of the presently disclosed subject matter, thecomputerized control system is further configured to route robots tostore crates in storage locations based on detecting the correlationbetween the range of crate sizes to which each crate is related andbetween the vertical spacing associated with an intended storagelocation.

In various embodiments of the presently disclosed subject matter, thecomputerized control system is configured to route robots to storecrates in storage locations sized in correlation with the size of thecrate to be stored, wherein crates intended for storage are routed forstorage in a smallest available storage location capable of storing anintended crate.

In various embodiments of the presently disclosed subject matter, thecomputerized control system is configured to route robots for relocatingcrates from storage locations of a first height to storage locationshaving a height smaller from the first and larger than a height of arelocation intended crate, whenever criteria are met.

In various embodiments of the presently disclosed subject matter, thecriteria include a storage location of a height smaller than the firstand larger than a height of a relocation intended crate becomesavailable.

In various embodiments of the presently disclosed subject matter, thecriteria include there is a shortage in storage locations of a heightsimilar to a height of a storage location where a carte that can bestored in a storage location of a smaller height can be stored.

In various embodiments of the presently disclosed subject matter atleast one pair of vertically oriented tracks is positioned next to theshelving unit in front of at least one of the groups of storagelocations which differ in size of the vertical spacing betweenhorizontally oriented storage surfaces.

In various embodiments of the presently disclosed subject matter thearray of vertically oriented tracks comprises uniformly spaced apartvertical tracks installed next to the shelving unit all along thelateral extent of the shelving block.

In various embodiments of the presently disclosed subject matter atleast a predetermined number of tracks from the array of horizontaltracks are positioned next to front edges of horizontally orientedstorage surfaces included in the regions which differ in spacing in thevertical direction between horizontally oriented storage surfaces.

In various embodiments of the presently disclosed subject matter thearray of horizontal tracks includes a plurality of horizontally orientedtrack segments non-uniformly spaced apart in the vertical direction.

In various embodiments of the presently disclosed subject matter atleast some of the tracks segments which are non-uniformly spaced apartin the vertical direction, are deployed substantially next to frontedges of respective horizontally oriented storage surfaces.

In various embodiments of the presently disclosed subject matter freeends of vertical rails included in the array of vertically orientedtracks extend a predetermined extent from above a topmost horizontallyoriented storage surface.

In various embodiments of the presently disclosed subject matter freeends of horizontal rails included in the array of horizontally orientedtracks extend a predetermined extent beyond a lateral end of theshelving block.

In various embodiments of the presently disclosed subject matter atleast a lowermost horizontal track extends evenly all along the lateralextent of the shelving block.

In various embodiments of the presently disclosed subject matter apredetermined number of horizontal surfaces located in a first region ofthe shelving block are vertically spaced apart each from a neighboringsurface a distance between 10% and 90% smaller than a distance betweenhorizontal neighboring surfaces of another predetermined number ofsurfaces located at a different region of the shelving block.

In various embodiments of the presently disclosed subject matter atopmost and a lowermost horizonal tracks intersect with a pair ofleftmost vertical tracks and with a pair of rightmost vertical tracks,thereby forming a closed-loop track arrangement through which aplurality of between two and a predetermined maximal number of robotscan comove either clockwise or counter clockwise such that none of thecomoving robots disturbs the motion of another.

In various embodiments of the presently disclosed subject matter atleast in regions of the shelving block where a vertical spacing betweenneighboring horizontal storage surfaces exceeds a predeterminedthreshold value, the shelving block comprises a plurality of uniformlyspaced apart vertical tracks installed next to front edges of thehorizontal storage surfaces constituting said regions.

In various embodiments of the presently disclosed subject matter thepredetermined threshold value is equal to the sum of (i) a heightbetween a bottom of a maximal height crate to be stored in the shelvingblock and a topmost portion of such crate where grasping arms of alift-robot loading-unit can take a grasp and load the crate; and (ii) amaximal vertical separation between a hypothetic horizontal track andthe grasping arms of said lift-robot loading-unit, when the lift robotis situated in the hypothetic horizontal track.

A second broad aspect the presently disclosed subject matter is acomputerized control system for robotic delivery and retrieval of cratesin a logistic center setup according to said first broad aspect.

In one exemplary embodiment the system is configured to register storagelocations and track data and to route robots through the tracks fordelivering crates to and retrieving crates from the storage locations,wherein the registration of storage locations includes differentiationbetween at least two groups of storage locations differing in thevertical distance between horizontally oriented storage surfaces in eachgroup.

In various embodiments of the presently disclosed subject matter thesystem is further configured to relocate crates for storageoptimization.

In various embodiments of the presently disclosed subject matter thesystem is further configured to route lift robots having lading-unitatop and lift robots having suspended loading unit to a meeting point onthe track network for exchanging a crate.

A third broad aspect of the presently disclosed subject matter is amethod for robotic delivery and retrieval of crates to and fromnon-uniformly sized storage spaces in a shelving array wherein thestorage spaces are accessible to lift robots through intersecting arraysof vertically oriented and horizontally oriented tracks.

In one exemplary embodiment method comprises: (i) having a minimum and amaximum of a vertical extent between a horizontal track and loading-unitgrippers of a lift-robot supposedly situated in the horizontal track;(ii) having a minimum and a maximum height between a bottom of a crateto be handled by the lift robot and a desired griping region withinwhich the crate walls are to be contacted by said grippers when graspingthe crate; (iii) determining a location on a horizontal storage surfacein a shelving unit, to which the crate is to be delivered or from whichretrieved by the lift robot; calculating a desired range of heights withrespect to the horizontal surface at which the lift-robot can besituated when handling the crate to or from the location; (iv)determining the availability of horizontal tracks and of vertical tracksin which the lift robot may be situated for aligning its grippers infront of the location within said range of heights; (v) selecting aspecific lift robot for handling the crate to or from the location; (vi)routing the lift robot through said arrays of intersecting tracks towithin the desired range of heights with respect to the location andsituating the lift robot in alignment with the location; and (vii)activating said arms for handling the crate to or from the location.

In various embodiments of the presently disclosed subject matter thedesired range of heights for delivering a crate to the location differsfrom the desired range of heights for retrieving the same crate from thelocation.

In various embodiments of the presently disclosed subject matter themethod is further comprising the step of determining what type robot issuitable for the delivery or retrieval of the crate; and performing themethod respect to at least two suitable robot types before the step ofselecting a specific robot for the delivery or retrieval of the crate.

BRIEF DESCRIPTION OF THE FIGURES

The present disclosed subject matter will be understood and appreciatedmore fully from the following detailed description taken in conjunctionwith the drawings in which corresponding or like numerals or charactersindicate corresponding or like components. Unless indicated otherwise,the drawings provide exemplary embodiments or aspects of the disclosureand do not limit the scope of the disclosure. In the drawings:

FIG. 1A illustrates a schematic side view of a shelving block comprisingtwo facing shelving units according to an embodiment of the presentlydisclosed subject matter with a lift robot situated on tracks inbetween.

FIG. 1B illustrates a schematic front view of the lift robot shown inFIG. 1A, with a crate grasped between the grippers of its suspendedloading-unit.

FIG. 1C illustrate a schematic profile view of a rail type that may beused for constructing track arrays according to various embodiments ofthe presently disclosed subject matter.

FIG. 1D outlines how some distances referred in the description are tobe measured.

FIG. 2A illustrates a schematic front view of a shelving unit withintersecting track arrays according to an embodiment of the presentlydisclosed subject matter.

FIG. 2B illustrate a schematic front view of a shelving unit withintersecting track arrays according to another embodiment of thepresently disclosed subject matter.

FIG. 2C illustrates selected parts from the shelving unit illustrated byFIG. 2B, with a lift-robot in position for handling a crate.

FIG. 3 illustrates a schematic front view of a lift robot having itsloading-unit atop for handling short height crates from upper shelves.

DETAILED DESCRIPTION

In modern logistic centers having automated crate delivery and retrievalsystem, there is a need in lift mechanisms for reaching verticallyspaced apart storage surfaces, located beyond the reach of surfacebogies moving on the floor.

In various embodiments of the presently disclosed subject matter, thelogistic center uses self-propelled lifters which can change theirdirection of motion through passive track array independently ofexternal mechanisms. In other various embodiments, the track arrayincludes guides in track junctions for steering the robot through thejunction in the desired direction. In some cases, the robot may beconfigured to actuate the guides in an autonomous manner. Additionallyor alternatively, the guides may be actuated by track-mounted actuatorsexternal to the robot.

Track array for self-propelled lifters (hereinafter referred to“lift-robots”) may comprise vertically oriented tracks. Vertical tracksprovide for vertical motion of robots, e.g. based on rack and piniondriving mechanism.

In the context of the present disclosure, the term “crate” relates to acontainer, a box, a tote, or a similar object capable of containingitems stored in the shelving unit.

In the context of the present disclosure, the term “track” relates to apair of parallel rails with a predetermined gap in between. In variousembodiments of the presently disclosed subject matter, two paralleltracks (comprising four rails in total) are located next to any storagelocation intended to be accessed by lift robots through motion in thevertical direction. The gap between the two tracks matches the distancebetween the rail wheels of the lift robot in a vertical plane parallelto the shelving block.

Locomotion through tracks is restrictive in that tracks must have awidth perpendicular to the direction of motion in match with thedistance between the rail wheels of lift-robot bogies, which in turnplaces restriction on the maximal width of crates that can be handled.

This restriction reflects on the efficiency of a logistic center interms of the three-dimensional space spent per a given volume of storedstuff. Robots are restricted to a motion about tracks, the width oftracks is constant, crates are accessible to lift robots moving in thevertical direction through the constant gap between pairs of neighboringtracks, resulting in that crates have a maximal width smaller than thegap between neighboring tracks. The problem is that in case storagelocations are approached by lift-robots moving in the verticaldirection, the maximal crate width is adopted also as the standard width(i.e. crates of only one uniform size are used), because the lateraldistance between on storage location to a next storage location is equalto the gap between neighboring tracks, regardless of the width of thestored crates.

Another restriction that may reflect on the efficiency of a logisticcenter in terms of the three-dimensional space spent per a given volumeof stored stuff, results from the specifications of robotic arms bywhich crates are loaded and carried (such as their range of motion). Asan example, a robot may include a locomotion unit with rail wheels inthe form of pinions for coupling to a track, and a loading-unit whichmay comprise robotic arms for handling crates to and from a storageposition. In some robot designs, the loading-unit is located underneaththe locomotion unit. A position of the grasping members of the roboticarms may thus be a predetermined distance below the location of the railwheels, and the predetermined range of operation of the loading-unitarms may therefore be restricted to a predetermine storage space below agiven location of a horizontal track.

As an example, when a storage spot is way below a closest horizontaltrack, a top of a crate stored at that spot may be out the reach of theloading-unit arms of the lift-robot. Substantial uniformity in a heightof crates may therefor be required, otherwise certain storage locationsmay become inaccessible to a lift-robot using a horizontal track.

It may be of interest to allow for compactization of storage spaces inlogistic centers for thereby improving the volume-efficiency of thelogistic center (i.e. store more items per a unit of storage volume).

It may also be of interest to allow the compactization with minimal lossof accessibility efficiency.

A first solution according to the presently disclosed subject matter isto provide for nonuniform vertical spacing between horizontal storagesurfaces with the intention to improve correlation between thedimensions of stored items and the dimensions of their storage cells,and to adopt the usage of crates of varied sizes, with the intension tooptimize correlation between the size of crates and the size of theitems contained by.

Another solution is to trace the distribution of crate-sizes flowingthrough the logistic center over a representing time period, and toadapt the distribution of sizes of storage location to the distributionof crate sizes, thereby increasing the practical storage capacity of thelogistic center.

Yet another solution is to relocate stored items in real-time from largestorage location to smaller storage locations, when smaller storagelocations become available.

A solution for storage spaces intended to contain no more than one crateper a width of lift-robots to be used, is to provide the shelving blockwith a pair of vertical track rails next to the non-uniformly verticallyspaced surfaces. In some cases, a distance between such neighboringtrack rails corresponds to the respective wheelbase dimension of thelift-robots. The gap between the two tracks may match the distancebetween the rail wheels of the lift robot in a vertical plane parallelto the shelving block.

In the context of the presently disclosed subject matter, tracks extendperpendicularly to a vertical surface next to front edges ofhorizontally oriented storage surfaces (shelves) and are often shared bytwo facing shelving units (being constituents of one shelving block),spaced by an aisle of the tracks' width, with the tracks spanning acrossthe aisle. Accordingly, each rail in said pair of vertical track railsnext to the non-uniformly vertically spaced surfaces, forms a track withthe other rail in the pair as well as with a mirroring rail located fromthe opposite side of the aisle.

In various embodiments of the presently disclosed subject matter, aplurality of uniformly spaced apart vertical tracks are positioned nextto front edges of the non-uniformly spaced storage surfaces. The tracksmay create columns of equal predetermined width through which thestorage spaces between said non-uniformly spaced surfaces becomeaccessible to lift robots. The predetermined distances between the railsconstituting the tracks are in match with a width of the robots,measured as respective distances between rail wheels of the lift robotsto be using the tracks, thereby allowing a lift robot to adapt thelocation of its loading-unit in front of any storage location opened tothe column between a pair of neighboring track rails, regardless of thevertical spacing between horizontal surfaces delimiting the storagelocation concerned.

When employing such architecture, crates may have a uniform width, butnot necessarily a uniform height. This provides a versatility in thesizes of crate, without altering the mechanical requirements with whichlift robots should comply.

As an example of the versatility achieved, a most common size may beagreed upon as a “standard size” crate, yet any other height may beused, either as a given fraction of the standard, as an integermultiplication thereof, or freely chosen.

In various embodiments of the presently disclosed subject matter, atleast some of the vertical tracks deployed about a shelving unit extendupwardly beyond a bottom of the upper storage space opened to betweenrails thereof, to an extent sufficient to allow a lift robot positioningits loading-unit arms for conveniently handling a delivery or retrievalof crate located on a storage surface constituting said bottom.Accordingly, in various embodiments of the presently disclosed subjectmatter vertical tracks extend from above a top of a shelving system,thereby allowing to use a topmost storage surface for crates of smallestexpected height, with a minimal vertical spacing between the shelvingtop and the topmost storage surface, thereby leaving more storage spacefor storage surfaces below the topmost.

In various embodiments of the presently disclosed subject matter, thetop of vertical tracks in the shelving block intersect a bottomhorizontal rack of a topmost horizontal rail thereby providing a Tjunction between each vertical track rail and the horizontal rail, whilea top horizontal ledge of the horizontal rail remains intact.

In various embodiments of the presently disclosed subject matter,vertical tracks in the storage array intersect a topmost horizontal railof the storage array, thereby providing a cross junction between eachvertical track rail and the horizontal rail. In some embodiments, a freeend of vertical rails constituting the vertical tracks of a shelvingblock of the presently disclosed subject matter, is blocked to preventescape of lift robot roadwheel. In some embodiments the blocking is by abolt secured through holes near the free end of the rail.

In various embodiments according to the presently disclosed subjectmatter, a horizontal track is deployed as part of the shelving blocknext to a front edge of each horizontal storage surface of a pluralityof horizontal storage surfaces, regardless of the vertical spacingbetween a concerned storage surface and storage surfaces next to it inthe vertical direction, whenever there is a vertical track present nearthe end of the horizontal surface such that the horizontal track mayprovide for a junction with the vertical track. Some of the horizontalrails may thus be unevenly spaced apart in the vertical direction.

In various embodiments of the presently disclosed subject matter, atleast some of the horizontal tracks deployed as a part of a storagearray, extend laterally beyond the end of the horizontal storagesurfaces. In various embodiments, the extent to which horizontal tracksextend laterally beyond the end of the horizontal storage surfaces is inmatch with the maximal extent to which lift robots in use need to shiftlaterally for alignment between a loading-unit of the robot and a centerof a crate of minimal expected width when stored near said end of ahorizontal storage surface, thereby minimizing the storage space to beoccupied by such crates. In various embodiments, the extent to whichhorizontal tracks extend laterally beyond the end of the horizontalstorage surfaces is in match with the minimal extent to which liftrobots in use need to shift laterally for temporarily evacuating a trackspot through which another robot or robots intend to travel.

In various embodiments of the presently disclosed subject matter a laneempty of horizontal storage surfaces separates between shelving blockslocated from opposite sides of the lane. The shelving blocks areextending perpendicularly to the lane, with aisles separating betweenshelving units from a same side of the lane opened to the lane. In someembodiments of the presently disclosed subject matter, horizontal tracksextend laterally beyond the end of the horizontal storage surfaces of ashelving block from one side of the lane, merge with respectivehorizontal tracks of a shelving block located from the opposite side ofthe lane, thereby allowing lift robots to either (i) travel across thelane for making routine deliveries and retrieval of crates; (ii) shiftlaterally for alignment between a loading-unit of the robot and a centerof a crate of minimal expected width when stored near the end of ahorizontal storage surface next to the lane; (iii) shift laterally fortemporarily evacuating a track spot through which another robot orrobots intend to travel.

In some embodiments of the presently disclosed subject matter, at leastsome of the extent to which a track extends beyond the ends of thestorage surfaces is utilized as a charging station. A portion of theextra track extent beyond the end of the storage surfaces is providedwith a pair of conductive strips, one strip per each of the two railsconstituting the track, is connected to a respective pole of electricalbattery charger, the strips are electrically isolated from the rails,thereby allowing robots having electrical collectors for charging, to berecharged while stationary situated on the extra portions of the tracks,and without interfering the system's transportation activity throughconnective track portions.

The above described solutions and features will be further explained inmore detail with reference to the figures.

FIG. 1A illustrates a schematic side view of a storage setup 100according to an exemplary embodiment of the presently disclosed subjectmatter. The storage setup comprises two facing shelving units 101 (dueto the side view, only the vertical side wall 101L of the left one andthe vertical side wall 101R of the right one are shown), a centralcomputer 160 in wireless communication with robots 190 and 199, and apair of intersecting track arrays. The intersecting track arrays includehorizontally oriented tracks 110, 120, 130 and 150, and verticallyoriented tracks Ta. Each track Ta comprises one rail 108R locatedadjacently to the right storage array 101R, and another rail 108Llocated adjacently to the left storage array 101L. In the schematic ofthe present disclosure, rails of vertical tracks are represented bycomb-like patterned lines when illustrated from their face or sideviews. When illustrated from their free-end view, rails of bothhorizontal and vertical tracks are represented by the shape illustratedin FIG. 1C (reduced in size according to image scale).

In various embodiments of the presently disclosed subject matter, all orsome of the horizontally oriented tracks are positioned, respectively,next to front edges of the horizontal storage surfaces of the storagearray.

In various embodiments of the presently disclosed subject matter, someor all of the horizontally oriented tracks are positioned, respectively,each adjacently to a front edge of a respective horizontal top or bottomplate of the shelving unit.

A lift robot 190 is situated on the vertical tracks Ta which extendtransversely to the passage 102 (referred to also as “aisle”) whichseparates between the facing shelving units. The lift robot 190 canclimb and descend along the tracks Ta in the vertical direction. Invarious embodiments of the disclosed subject matter, the lift robot 190can travel also laterally along the horizontal tracks. In variousembodiments of the disclosed subject matter, lift robots are capable ofswitching their motion mode from vertical to horizontal and vice versa,in intersections between the vertical and horizontal tracks.

The lift robot 190 comprises a loading unit 191 that can slide its arms192 and/or grippers 193 to the left and to the right for accessing intothe storage spaces and deliver or retrieve crates to/from the horizontalstorage surfaces of either of the facing shelving units. A plurality oflift robots may perform simultaneously on the track arrays between apair of facing shelving units. In various embodiments of the presentlydisclosed subject matter, lift robots cooperate with floor robots 199 inthe delivery and retrieval of crates. The floor robots 199 may travelthrough the aisle 102, stop below a lift robot 190 for letting the liftrobot 190 to pick a crate for storage, or receive a retrieved crate froma lift robot 190 for delivering it to another location in the logisticcenter, e.g. a picking station.

In various embodiments of the presently disclosed subject matter, bottomstorage surface of a shelving unit may be gapped a predetermineddistance above the floor. The shelving unit may include support legs103. The height of support legs 103 can predetermine the distance of thebottom storage surface L0 from above the floor. In various embodimentsof the presently disclosed subject matter, when empty from crates, floorrobots 199 may travel through the gap between bottom storage surface L0and the floor. Additionally or alternatively, the height of support legs103 may be designed to allow floor robots 199 to travel through the gap,when crates are loaded thereon, such as crates of a maximal height. Asan example, the maximal height may be the standard height of the crates,may be a median height of the crates in the shelving block or based onother common characteristics of the crates in the shelving block, or thelike.

Each of the shelving units comprises a plurality of horizontal storagesurfaces L0 to L4 nonuniformly spaced in the vertical direction. Forexample, the distance between the bottom storage surface L0 and thestorage surface L1 neighboring from above is closely the same as thedistance between storage surface L2 and the storage surface L3, yet bothdiffer from the distances between the other pairs of neighboringsurfaces.

The distribution in the heights of the storage surfaces allows to storein the shelving block crates of a variety of heights, and to locate eachcrate in a storage space mostly adapted to the specific crate height.For example, the tallest crates can be stored on the storage surface L1,and the lowest crates can be stored on the storage surface L4 (if theirheight is smaller than the distance between the storage surface L4 andthe top plate 101 t of the storage array).

In various embodiments of the presently disclosed subject matter, eachof the shelving units of a block (and which therefore share the sameintersecting track array) comprises horizontally oriented storagesurfaces uniformly spaced apart in the vertical direction. Two shelvingunits in a same shelving block may yet differ in the size of thevertical spacing. For example, the vertical spacing between horizontallyoriented storage surfaces in one of the two shelving units may be 25%,50%, 75% or any desired percentage of the vertical spacing betweenhorizontally oriented storage surfaces in the facing shelving unit. Thelift robots that serve both units of the shelving block may thus berouted by the computerized control system to store crates of a givenrange of sizes in a first of the facing shelving units, and to storecrates of a different given range of sizes in the second of the facingshelving units. In some exemplary embodiments, the two shelving unitswhich face each other, may define the routes that the lift robots maytravel, as the locations where a track is available on both shelvingunits. In view of the non-uniform vertical distribution of tracks onboth shelving units, the lift robots may travel on non-uniform grid oftracks, that has non-uniform vertical spacing, non-uniform horizontalspacing, or the like. In some exemplary embodiments, non-uniformhorizontal spacing may be exhibited, even when the lift robot requires apredetermined horizontal spacing when traveling in vertical motion, suchas based on non-uniform distribution of pairs of vertical tracks havingthe predetermined horizontal spacing therebetween.

Additionally or alternatively, the shelving block may comprise twomirroring shelving units, each of which having non-uniform verticaldistribution of shelving and/or tracks.

In various embodiments of the presently disclosed subject matter, thevertical tracks Ta may extend upwardly beyond the top 101 t of theshelving block. This extension of the tracks may allow the lift robotsto approach with their grippers 193 closely under the top plate 101 t,for handling crates that nearly fill up with their height the uppermoststorage surface of the shelving block.

FIG. 1B illustrates a schematic front view of the lift robot 190 shownin FIG. 1A, with a crate 175 grasped between its loading-unit arms 192.Referring to FIG. 1D, there may be a desired region on the side walls ofcrate 176 within which the crate is to be gripped by the grippers 193 ofthe loading-unit arms 192. The desired region within which the crate isto be gripped may be between first and second predetermined heights h1and h2 measurable from the bottom 176 b of the crate. The dashed line HRrepresents the height of a horizontal track in which the rail wheels ofthe robot 190 are situated. A vertical distance between the rail heightreference line HR may have a maximum S1 and a minimum S2 in case theloading-unit is capable of varying the position of the loading arms 192in the vertical direction. In embodiments in which the loading arms areimmovable in the vertical direction, S1 is equal to S2.

It can be appreciated that for picking a crate from a horizontal storagesurface while griping the crate within said desired gripping region, thelift robot may be situated in the track array with its grippers 193 infront of the desired gripping region. The vertical distance between thestorage surface on which the bottom 176 b of the crate 176 rests, andbetween the grippers 193 need to be within the desired gripping range h2minus h1. For this to be achieved, the lift robot may be situated in thetrack array such that a vertical distance d between the rail heightreference line HR and the horizontal storage surface on which the bottom176 b of the crate rests is within the range h2+s2 and h1+s1. This rangewill be referred to also hereinafter “handling range”.

It can be appreciated that for delivering a crate to a storage space,the vertical separation d between the rail height HR and the horizontalstorage surface on which the crate is to be placed may be greater tosome extent than the separation between them in case of retrieval of thesame crate from the same storage surface. This is because whendelivering a crate, it can be released from the grippers 193 when thebottom of the crate is a few centimeters from above the storage surface,leaving its delivery accomplished by gravity. The allowed distance maydepend on the sensitivity of content of the crate to the shock that mayresult from the fall, and on other factors that may be considered bymanagers of the logistic center. This difference between delivery andretrieval may result with more flexibility in designing robot routes.For example, the control system of a logistic center may be programmedto allow 5 cm free fall for a group of crates containing specific goods.The control system may then instruct the robot to deliver a crate fromthe allowed group by approaching the intended storage space eitherthrough a horizontal track that its vertical separation from theintended storage surface allows for a delivery with no more than 5 cmdrop, or through a vertical track, since vertical tracks allow the robotto accurately adapt its position from above the storage surface to anydesired height. For retrieval of same crate, the control system mayinstruct the robot to approach the related storage space only through avertical track, if the height HR of the horizontal track is beyond thehandling range.

FIG. 1C illustrate a schematic profile view of a rail type 110 accordingto an exemplary embodiment that may be used for constructing trackarrays according to various embodiments of the presently disclosedsubject matter. The illustrated rail comprises (i) a backwall 110 b (invarious embodiments of the presently disclosed subject matter may beused for fixing the rail to external infrastructure, e.g. by means ofscrews; (ii) a travel ledge protruding perpendicularly from a first endof the backwall and divided into a road rail part 110 w for a bearingwheel to travel along, and a rack part 110 r to which a motor drivenpinion is couplable for driving the robot along; and (iii) a cover ledge110 t protruding perpendicularly from a second end of the backwallopposite said first end, for the bearing wheel to travel along when therobot is in vertical motion mode.

FIG. 2A illustrates a schematic front view of a storage array 200according to another exemplary embodiment of the presently disclosedsubject matter. The storage array comprises a shelving unit 201 and apair of intersecting track arrays. The track arrays comprise an array ofvertically oriented tracks Ta, and an array of horizontally orientedtracks 205, 208, 209, 210. The vertically oriented tracks Ta divide theshelving block into a plurality of storage columns C1 to C6. The tracksTa are spaced laterally with equal spaces in between, making the storagecolumns of a uniform width. In various embodiments of the presentlydisclosed subject matter, the top end of each of the vertical tracks Taforms a junction with the uppermost horizontally oriented track 210,located substantially evenly with a top plate 201 t of the shelvingblock.

In the schematic of the present disclosure, rails of horizontal tracksare represented by a framed dashed line. Edges of storage surfaces andof walls of the shelving unit are represented by a plain double linesuch as 204.

In some exemplary embodiments, the uppermost horizontal track 210 formswith the rightmost and the leftmost pairs of vertical tracks Ta, aloop-track closed with the lowermost horizontal track 205. In someexemplary embodiments, this loop of tracks allows a plurality of liftrobots to encircle the shelving block in a predetermined direction,either clockwise or counterclockwise with minimal or no interferencebetween their routes. Additionally or alternatively, the disclosedsubject matter may be employed when the robots are not configured tomove in a general circle movement throughout the rails. For example, insome embodiments, the robots may be configured to move freely on thetracks in any direction.

In the illustrated embodiment, the lowermost track 205 is locatedadjacently to the front edge of the second storage surface from thebottom of the array. There is no horizontal rail next to the front edgeof the lowermost storage surface formed by a bottom plate 201 b of theshelving block, since the lift robots have a vertical size (see distanceS2 of robot 190 in FIG. 1D) greater than the height of the legs 203,thus may not fit into a track located only such a height above thefloor. In various embodiments of the presently disclosed subject matter,lift robots are of a type having its loading unit from above (i.e. likean upside-down version of the robot 190, see FIG. 3). In suchembodiments, the lift robot may fit into a horizontal track positionedclose to the floor.

In various embodiments of the disclosed subject matter, lift robotshaving their loading-unit atop, cooperate with lift robots havingsuspended loading-unit in the delivery and retrieval of crates.

Some of the horizontal storage surfaces in the shelving array are spacednonuniformly in the vertical direction. The storage spaces in theshelving structure 201 are therefore of varied heights. The most commonvolume spaces are of the size D, e.g. the topmost storage space incolumn C1, which can store crates sized up to the size of crate 272.Other storage spaces can be of any desired size up to the full heightbetween the bottom and top plates 201 b and 201 t of the shelving unit.Crate sizes may be limited not only by the dimensions of the storagespaces but also on the limitation of the robots in terms of dimensionsand of weights that can be handled.

In the illustrated embodiment, the shortest height storage space ishosts crate 271. The tallest storage space is the one marked A, whichstores crate 273. The storage space sized A is as twice high as thestorage spaces sized D. The storage space sized C as of half the heightof D. The second storage space from the bottom of column C3 sized B isof a slightly greater height than the height of D.

Regardless of the height of the storage space, all storage spaces areaccessible to the lift robots through vertical motion along the verticaltracks. However, if the robot 190 is to be used, the storage spaces onthe topmost row of the shelving array may not be as small as the storagespace that hosts the crate 271 (or even bigger), due to the limitationmentioned above with reference to FIG. 1D. In case short height cratesare to be stored in the topmost row of a shelving unit, an embodimentsuch as illustrate in FIGS. 1A and 2B, with vertical upwardly protrudingtrack rails, may be used. In the embodiment of FIG. 2A, horizontaltracks 205 209 and 210, which intersect with the rightmost vertical rail(to the right of column C6) comprise respective extensions 205 e 209 eand 210 e, which protrude beyond the right wall 201R of the shelvingblock. Depending on the intended use of the extensions and on thesurroundings of the shelving block, the horizontal tracks may or may notextend also to protrude beyond the left wall 201L of the shelving block.

FIG. 2B illustrate a schematic front view of a storage array accordingto additional exemplary embodiment of the presently disclosed subjectmatter. The embodiment of FIG. 2B differs from that of FIG. 1A in thedivision of the storage spaces, in the arrangement of the vertical andof the horizontal track arrays, and consequently in the maneuveringtaken by the lift robots for accessing the variety of storage spacesprovided. The embodiment assumes the grippers of the lift robot arecapable of coming closer in the lateral direction, for handling crateshaving a width in the range between 40% and 100% the width of the crates(e.g. 278) presented in FIG. 2A.

The shelving unit 221 comprises six columns C1 to C6. In some exemplaryembodiments, only a portion of the columns (e.g., C1 and C6 in thepresent illustrated embodiment) are provided with pairs of verticaltracks which allow for accessibility to all storage spaces throughvertical motion. Column C2 is provided with vertical track 242 whichtogether with the neighboring track 241 provides for accessibility toits storage spaces by vertical motion mode only for the first threestorage spaces from the bottom plate 221 b. For accessing the crate 280hosted in the fourth storage space, the lift robot may be required toalign with column C2 trough the horizontal track 230 (for meeting thelimitations associated with the description of FIG. 1D).

The horizontal track 230 is extended to the left and protrude beyond theleft wall 221L of the shelving block, to an extent annotated 230L. Theextension 230L allows the lift robot 190 to align symmetrically in frontof crate 281 (see in FIG. 2C projection of rail 230 and crate 281, withthe axis of symmetry 281 a of the crate in alignment with the axis ofsymmetry of the robot) and access it by bringing its grippers togetherin the lateral direction to about the width of crate 281, then movingthem forward for gripping and pulling the crate from the storage space.Reversing said operation in time provides for delivery of the crate intothe storage space. As can be appreciated, another crate of similar widthcan be stored to the right of crate 281. Crates of shorter height may behandled to and from the same storage space by situating the robotthrough the horizontal track 229.

Shorter crates, such as 282, may be stored in the storage spaces betweentracks 229 and 230, and are accessible to robots situated in thehorizontal track 231 next to the top plate 221 t of the shelving unit.Crate 282 may be accessed also through vertical motion mode using thepair of vertical tracks 240 and 241, by robot models having thecapability of shifting the grippers off the axis of symmetry of therobot.

The storage space between horizontal tracks 230 and 231 may beaccessible to lift robot models having the loading-unit from above thelocomotion part, by traveling through horizontal track 229.

In various embodiments of the disclosed subject matter, lift robotshaving their loading-unit atop, cooperate with lift robots havingsuspended loading-unit in the delivery and retrieval of crates.

For example, lift robot having a loading-unit atop may retrieve a cratestored in the storage space between horizontal tracks 230 and 231 (i.e.by traveling laterally through track 229 to align with and pick theintended crate), then switch direction in an intersection between track229 and either of the vertical pair of tracks, e.g. 241-242, and descendto some mid portion thereof. Another lift robot having a suspendedloading-unit may then approach from above and pick the crate in ananalogous manner as picking a crate from a floor robot. The lift robotwith the suspended loading unit can then perform with the crate as itregularly performs with picked crates, while the lift robot having theloading-unit atop, may continue to either accept a crate from anotherrobot for delivering it to the storage space between the horizontaltracks 230 and 231, or to retrieve another crate from this storage spaceand repeat the above described exchange with a lift robot havingsuspended loading-unit.

Crates 279 of a mid-width between that of 282 and that of 280 are storedin the storage space between horizontal tracks 228 and 229. They may behandled by robots situated in an adjacent horizontal track, such as 230,229, 228, 227, or the like.

Likewise, storage space between horizontal tracks 226 and 227 may beaccessible through adjacent horizontal track, such as 228.

All the storage spaces between bottom plate 221 b and horizontal tracksegment 226, are accessible (depending on their height, which is knownto the system controller which route the robots accordingly) to robotssituated in either horizontal track segment 226, or in horizontal track227. The horizontal track 226 is a portion of horizontal track 225 whichextend about storage spaces inaccessible through vertical motion modesdue to lack of vertical tracks.

Storage spaces in columns C1 and C6, as well as in the lower portion ofcolumn C2 are accessible to robots situated in the relevant verticaltracks pair, from pairs 240-241, 241-242, and 243-244.

The track pairs 240-241 and 243-244 extend upwardly beyond the top plate221 t, thereby providing for handling short height crates located incolumns C1 and C6 on a storage surface next to horizontal track 230.

Track extensions such as 231 e and 225 e may be provided and protrudelaterally beyond the right vertical wall 221R to any desired extent,e.g. for robot maneuvering when switching motion mode from horizontal tovertical, or e.g. for allowing robots to align with narrow crates storedto the left of side wall 221R.

The vertical tracks 240, 241, 242, 243 and 244, intersect with the lowerhorizontal track 225. In various embodiments of the presently disclosedsubject matter, the vertical tracks are extended to a predeterminedextent below the lowest horizontal track, this may allow robots tohandle crates of shorter height, allow maneuvering e.g. for exchangingcrates with floor robots, and for any other desired purposes. In variousembodiments of the presently disclosed subject matter, the bottom endsof a vertical track do not extend beyond the bottom of the lowest trackwith which they intersect.

The uppermost horizontal track 231 forms with the right and the leftpairs of vertical tracks 240-241 and 243-244, a loop-track closed withthe lowermost horizontal track 225. This loop of tracks may allow aplurality of lift robots to encircle the shelving block in apredetermined direction, either clockwise or counterclockwise withminimal or no interference between their routes. However, in otherembodiments, the robots may move freely in any desired direction acrossthe tracks and not be limited to a general encircling motion.

FIG. 3 illustrates a schematic front view of a lift robot 390 having itsloading-unit 391 atop for handling short height crates from uppershelves. When its wheels 395 are situated in a track below the locationof the storage space to be approached, it can slide its loading unitarms 392 toward the storage space for delivering or retrieving a crate.Therefore, while lift robots 190 with suspended loading-unit may beincapable of approaching a location due to lacking of tracks within thedesired distance (as mentioned above with reference to FIG. 1D) fromabove the location, the intended task may be performed by a robot suchas 390 approaching the location through track/s located applicablyunderneath the location.

With the dense size-depended arrangement of crates within the storagearray based on the arrangements and procedures described herein, thelogistic center may become highly space-efficient. Moreover, with cratesstored denser, the average traveling distance per a delivery/retrievaltask decreases, resulting with saving in energy and maintenance costs.In various embodiments of the presently disclosed subject matter, thecomputerized control system may be configured to improve the spaceefficiency by automatic relocation of crates. The improvement may beachieved by relocating crates of a given size range from a shelving unithaving a given uniform vertical spacing unnecessary large for therelated crates, to a facing shelving unit having a given smaller uniformvertical spacing when the latter become available. In embodiments of thedisclosed subject matter in which one shelving unit has regionsdiffering in the vertical spacing, the improvement may be achieved byrelocating a given size range from a region of a given vertical spacingto a region of a smaller vertical spacing in the same shelving unit,thereby optimizing the storage space-efficiency furthermore.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present disclosed subject matter. It should also benoted that, in some alternative implementations, the functions noted inthe block may occur out of the order noted in the figures. For example,two blocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be performed in the reverseorder, depending upon the functionality involved.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosedsubject matter. As used herein, the singular forms “a”, “an” and “the”are intended to include the plural forms as well, unless the contextclearly indicates otherwise. It will be further understood that theterms “comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosed subject matter has been presentedfor purposes of illustration and description, but is not intended to beexhaustive or limited to the disclosed subject matter in the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art without departing from the scope and spiritof the disclosed subject matter. The embodiment was chosen and describedin order to best explain the principles of the disclosed subject matterand the practical application, and to enable others of ordinary skill inthe art to understand the disclosed subject matter for variousembodiments with various modifications as are suited to the particularuse contemplated.

The invention claimed is:
 1. A storage setup for logistic centers usinglift robots for storing and retrieving crates, the storage setupcomprises: at least one shelving block comprising at least one shelvingunit, each shelving unit having a plurality of horizontally orientedvertically spaced apart storage surfaces configured to store thereoncrates; a network of intersecting track arrays deployed next to theblock's shelving for allowing robotic delivery and retrieval of cratesto and from storage locations in the shelving block, wherein the networkof intersecting track arrays comprises an array of horizontal trackscomprising a plurality of horizontally oriented track segmentsnon-uniformly spaced apart in the vertical direction; and a computerizedcontrol system in which storage locations and track data are registeredsuch that robots can be routed by the computerized control systemthrough the tracks for delivering crates to and retrieving crates fromthe storage locations; wherein at least two groups of storage locationsin the shelving block differ in the size of the vertical spacing betweenhorizontally oriented storage surfaces such that crates of a heightshorter than the size of the vertical spacing in at least one of thegroups but taller than the size of the vertical spacing in other of thegroups can be robotically stored to and retrieved from a horizontallyoriented storage surface constituting a storage location in which thevertical spacing is of a size greater than a height of the crate;wherein the computerized control system is configured to differentiatebetween storage locations based on which crate sizes from at least twodifferent ranges of crate sizes a storage location is capable ofstoring.
 2. The storage setup for logistic centers according to claim 1,wherein at least one pair of vertically oriented tracks is positionednext to the shelving unit in front of at least one of the groups ofstorage locations which differ in size of the vertical spacing betweenhorizontally oriented storage surfaces.
 3. The storage setup forlogistic centers according to claim 1, wherein the array of verticallyoriented tracks comprises uniformly spaced apart vertical tracksinstalled next to the shelving unit all along the lateral extent of theshelving block.
 4. The storage setup for logistic centers according toclaim 1, wherein at least a predetermined number of tracks from thearray of horizontal tracks are positioned next to front edges ofhorizontally oriented storage surfaces included in the regions whichdiffer in spacing in the vertical direction between horizontallyoriented storage surfaces.
 5. The storage setup for logistic centersaccording to claim 1, wherein at least some of the tracks segments whichare non-uniformly spaced apart in the vertical direction, are deployedsubstantially next to front edges of respective horizontally orientedstorage surfaces.
 6. The storage setup for logistic centers according toclaim 1, wherein free ends of vertical rails included in the array ofvertically oriented tracks extend a predetermined extent from above atopmost horizontally oriented storage surface.
 7. The storage setup forlogistic centers according to claim 1, wherein free ends of horizontalrails included in the array of horizontally oriented tracks extend apredetermined extent beyond a lateral end of the shelving block.
 8. Thestorage setup for logistic centers according to claim 1, wherein atleast a lowermost horizontal track extends evenly all along the lateralextent of the shelving block.
 9. The storage setup for logistic centersaccording to claim 1, wherein a topmost and a lowermost horizontaltracks intersect with a pair of leftmost vertical tracks and with a pairof rightmost vertical tracks, thereby forming a closed-loop trackarrangement through which a plurality of between two and a predeterminedmaximal number of robots can co-move either clockwise or counterclockwise such that none of the co-moving robots disturbs the motion ofanother.
 10. The storage setup for logistic centers according to claim1, wherein at least in regions of the shelving block where a verticalspacing between neighboring horizontal storage surfaces exceeds apredetermined threshold value, the shelving block comprises a pluralityof uniformly spaced apart vertical tracks installed next to front edgesof the horizontal storage surfaces constituting said regions.
 11. Thestorage setup for logistic centers according to claim 1, wherein thecomputerized control system is further configured to route robots tostore crates in storage locations based on detecting the correlationbetween the range of crate sizes to which each crate is related andbetween the vertical spacing associated with an intended storagelocation.
 12. The storage setup for logistic centers according to claim11, wherein the computerized control system is configured to routerobots to store crates in storage locations sized in correlation withthe size of the crate to be stored, wherein crates intended for storageare routed for storage in a smallest available storage location capableof storing an intended crate.
 13. The storage setup for logistic centersaccording to claim 12, wherein the computerized control system isconfigured to route robots for relocating crates from storage locationsof a first height to storage locations having a height smaller from thefirst and larger than a height of a relocation intended crate, whenevercriteria are met.
 14. The storage setup for logistic centers accordingto claim 13, wherein the criteria include a storage location of a heightsmaller than the first and larger than a height of a relocation intendedcrate becomes available.
 15. The storage setup for logistic centersaccording to claim 13, wherein the criteria include there is a shortagein storage locations of a height similar to a height of a storagelocation where a crate that can be stored in a storage location of asmaller height can be stored.
 16. A storage setup for logistic centersusing lift robots for storing and retrieving crates, the storage setupcomprises: at least one shelving block comprising at least one shelvingunit, each shelving unit having a plurality of horizontally orientedvertically spaced apart storage surfaces configured to store thereoncrates, wherein a predetermined number of horizontal surfaces located ina first region of the at least one shelving block are vertically spacedapart each from a neighboring surface a distance between 10% and 90%smaller than a distance between horizontal neighboring surfaces ofanother predetermined number of surfaces located at a different regionof the at least one shelving block; a network of intersecting trackarrays deployed next to the block's shelving for allowing roboticdelivery and retreival of crates to and from storage locations in theshelving block; and a computerized control system in which stoagelocations and track data are registered such that robots can be routedby the computerized control system through the tracks for deliveringcrates to and retrieving crates from the storage locations; wherein atleast two groups of storage locations in the shelving block differ inthe size of the vertical spacing between horizontally oriented storagesurfaces such that crates of a height shorter than the size of thevertical spacing in other of the groups can be robotically stored to andretrieved from a horizontally oriented storage surface constituting astorage location in which the vertical spacing is of a size greater thana height of the crate; wherein the computerized control system isconfigured to differentiate between storage locations based on whichcrate sizes from at least two different ranges of crate sizes a storagelocation is capable of storage.
 17. A storage setup for logistic centersusing lift robots for storing and retrieving crates, the storage setupcomprises: at least one shelving block comprising at least one shelvingunit, each shelving unit having a plurality of horizontally orientedvertically spaced apart storage surfaces configured to store theroncrates; a network of intersecting track arrays deployed next to theblock's shelving for allowing robotic delivery and retrieving of cratesto and from storage locations in the shelving blocks; and a computerizedcontrol system in which storage locations and track data are registeredsuch that robots can be routed by the computerized control systemthrough the tracks for delivering crates to and retrieving crates fromthe storage locations; wherein at least two groups of storage locationsin the shelving block differ in the size of the vertical spacing betweenhorizontally oriented storage surface such that crates of a heightshorter than the size of the vertical spacing in at least one of thegroups but taller than the size of the vertical spacing in other of thegroups can be robotically stored to and retrieved from a horizontallyoriented storage surface constituting a storage location in which thevertical spacing is of a size greater than a height of the crate;wherein the computerized control system is configured to differntiatebetween storage locations based on which crate sizes from at least twodifferent ranges of crates sizes a storage location is capable ofstoring; wherein at least in regions of the shelving block where avertical spacing between neighboring horizontal storage surfaces exceedsa predetermined threshold value, the shelving block comprises aplurality of uniformly spaced apart vertical tracks installed next tofront edges of the horizontal storage surfaces constituting saidregions, wherein the predetermined threshold value is equal to the sumof (i) a height between a bottom of a maximal height crate to be storedin the shelving block and a topmost portion of such crate where graspingarms of a lift-robot loading-unit can take a grasp and load the crate;and (ii) a maximal vertical separation between a hypothetic horizontaltrack and the grasping arms of said lift-robot loading-unit, when thelift robot is situated in the hypothetic horizontal track.
 18. Acomputerized control system for robotic delivery and retrieval of cratesin a logistic center setup, wherein the system is configured to registerstorage locations and track data and to route robots through tracks fordelivering crates to and retrieving crates from the storage locations,wherein the registration of storage locations includes differentiationbetween at least two groups of storage locations differing in thevertical distance between horizontally oriented storage surfaces in eachgroup; wherein the logistic center setup is configured to utilize liftrobots for storing and retrieving crates in and from at least oneshelving block comprising at least one shelving unit, whereon each ofthe at least on shelving unit has a plurality of horizontally orientedvertically spaced apart storing surfaces configured to store thereoncrates; and wherein a network of intersecting track arrays is deployednext to the shelving block for allowing robotic delivery and retrievalof crates to and from storage locations in the shelving block, whereinthe network of intersecting track arrays comprises an array ofhorizontal tracks comprising a plurality of horizontally oriented tracksegments non-uniformly spaced apart in the vertical direction.
 19. Thecomputerized control system for robotic delivery and retrieval of cratesin a logistic center according to claim 18, wherein the system isfurther configured to relocate crates for storage optimization.
 20. Thecomputerized control system for robotic delivery and retrieval of cratesin a logistic center according to claim 18, wherein the system isfurther configured to route lift robots having loading-unit atop andlift robots having suspended loading unit to a meeting point on thetrack network for exchanging a crate.
 21. A method for robotic deliveryand retrieval of crates to and from non-uniformly sized storage spacesin a shelving array wherein the storage spaces are accessible to liftrobots through intersecting arrays of vertically oriented andhorizontally oriented tracks, the method comprises: having a minimum anda maximum of a vertical extent between a horizontal track andloading-unit grippers of a lift-robot configured to be situated in thehorizontal track; having a minimum and a maximum height between a bottomof a crate to be handled by the lift robot and a desired gripping regionwithin which the crate walls are to be contacted by said grippers whengrasping the crate; determining a location on a horizontal storagesurface in a shelving unit, to which the crate is to be delivered orfrom which retrieved by the lift robot; calculating a desired range ofheights with respect to the horizontal surface at which the lift-robotis configured to be situated when handling the crate to or from thelocation; determining the availability of horizontal tracks and ofvertical tracks in which the lift robot is configured to be situated foraligning its grippers in front of the location within said range ofheights; selecting a specific lift robot for handling the crate to orfrom the location; routing the lift robot through said arrays ofintersecting tracks to within the desired range of heights with respectto the location and situating the lift robot in alignment with thelocation; and activating said arms for handling the crate to or from thelocation.
 22. The method for robotic delivery and retrieval of cratesaccording to claim 21, wherein the desired range of heights fordelivering a crate to the location differs from the desired range ofheights for retrieving the same crate from the location.
 23. The methodfor robotic delivery and retrieval of crates according to claim 21,further comprising the step of determining what type robot is suitablefor the delivery or retrieval of the crate; and performing the methodwith respect to at least two suitable robot types before the step ofselecting a specific robot for the delivery or retrieval of the crate.